mirror of
https://github.com/XTLS/Xray-core.git
synced 2024-11-05 04:29:19 +02:00
367 lines
9.2 KiB
Go
367 lines
9.2 KiB
Go
package shadowsocks
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import (
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"crypto/cipher"
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"crypto/hmac"
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"crypto/rand"
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"crypto/sha256"
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"hash/crc32"
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"io"
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"github.com/xtls/xray-core/common"
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"github.com/xtls/xray-core/common/buf"
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"github.com/xtls/xray-core/common/crypto"
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"github.com/xtls/xray-core/common/dice"
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"github.com/xtls/xray-core/common/net"
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"github.com/xtls/xray-core/common/protocol"
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)
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const (
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Version = 1
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)
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var addrParser = protocol.NewAddressParser(
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protocol.AddressFamilyByte(0x01, net.AddressFamilyIPv4),
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protocol.AddressFamilyByte(0x04, net.AddressFamilyIPv6),
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protocol.AddressFamilyByte(0x03, net.AddressFamilyDomain),
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protocol.WithAddressTypeParser(func(b byte) byte {
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return b & 0x0F
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}),
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)
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type FullReader struct {
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reader io.Reader
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buffer []byte
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}
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func (r *FullReader) Read(p []byte) (n int, err error) {
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if r.buffer != nil {
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n := copy(p, r.buffer)
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if n == len(r.buffer) {
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r.buffer = nil
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} else {
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r.buffer = r.buffer[n:]
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}
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if n == len(p) {
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return n, nil
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} else {
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m, err := r.reader.Read(p[n:])
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return n + m, err
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}
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}
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return r.reader.Read(p)
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}
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// ReadTCPSession reads a Shadowsocks TCP session from the given reader, returns its header and remaining parts.
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func ReadTCPSession(validator *Validator, reader io.Reader) (*protocol.RequestHeader, buf.Reader, error) {
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hashkdf := hmac.New(sha256.New, []byte("SSBSKDF"))
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behaviorSeed := crc32.ChecksumIEEE(hashkdf.Sum(nil))
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behaviorRand := dice.NewDeterministicDice(int64(behaviorSeed))
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BaseDrainSize := behaviorRand.Roll(3266)
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RandDrainMax := behaviorRand.Roll(64) + 1
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RandDrainRolled := dice.Roll(RandDrainMax)
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DrainSize := BaseDrainSize + 16 + 38 + RandDrainRolled
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readSizeRemain := DrainSize
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var r2 buf.Reader
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buffer := buf.New()
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defer buffer.Release()
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var user *protocol.MemoryUser
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var ivLen int32
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var err error
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count := validator.Count()
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if count == 0 {
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readSizeRemain -= int(buffer.Len())
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DrainConnN(reader, readSizeRemain)
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return nil, nil, newError("invalid user")
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} else if count > 1 {
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var aead cipher.AEAD
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if _, err := buffer.ReadFullFrom(reader, 50); err != nil {
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readSizeRemain -= int(buffer.Len())
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DrainConnN(reader, readSizeRemain)
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return nil, nil, newError("failed to read 50 bytes").Base(err)
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}
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bs := buffer.Bytes()
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user, aead, _, ivLen, err = validator.Get(bs, protocol.RequestCommandTCP)
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if user != nil {
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reader = &FullReader{reader, bs[ivLen:]}
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auth := &crypto.AEADAuthenticator{
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AEAD: aead,
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NonceGenerator: crypto.GenerateInitialAEADNonce(),
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}
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r2 = crypto.NewAuthenticationReader(auth, &crypto.AEADChunkSizeParser{
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Auth: auth,
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}, reader, protocol.TransferTypeStream, nil)
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} else {
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readSizeRemain -= int(buffer.Len())
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DrainConnN(reader, readSizeRemain)
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return nil, nil, newError("failed to match an user").Base(err)
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}
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} else {
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user, ivLen = validator.GetOnlyUser()
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account := user.Account.(*MemoryAccount)
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hashkdf.Write(account.Key)
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var iv []byte
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if ivLen > 0 {
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if _, err := buffer.ReadFullFrom(reader, ivLen); err != nil {
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readSizeRemain -= int(buffer.Len())
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DrainConnN(reader, readSizeRemain)
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return nil, nil, newError("failed to read IV").Base(err)
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}
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iv = append([]byte(nil), buffer.BytesTo(ivLen)...)
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}
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r, err := account.Cipher.NewDecryptionReader(account.Key, iv, reader)
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if err != nil {
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readSizeRemain -= int(buffer.Len())
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DrainConnN(reader, readSizeRemain)
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return nil, nil, newError("failed to initialize decoding stream").Base(err).AtError()
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}
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r2 = r
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}
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br := &buf.BufferedReader{Reader: r2}
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request := &protocol.RequestHeader{
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Version: Version,
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User: user,
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Command: protocol.RequestCommandTCP,
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}
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readSizeRemain -= int(buffer.Len())
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buffer.Clear()
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addr, port, err := addrParser.ReadAddressPort(buffer, br)
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if err != nil {
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readSizeRemain -= int(buffer.Len())
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DrainConnN(reader, readSizeRemain)
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return nil, nil, newError("failed to read address").Base(err)
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}
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request.Address = addr
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request.Port = port
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if request.Address == nil {
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readSizeRemain -= int(buffer.Len())
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DrainConnN(reader, readSizeRemain)
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return nil, nil, newError("invalid remote address.")
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}
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return request, br, nil
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}
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func DrainConnN(reader io.Reader, n int) error {
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_, err := io.CopyN(io.Discard, reader, int64(n))
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return err
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}
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// WriteTCPRequest writes Shadowsocks request into the given writer, and returns a writer for body.
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func WriteTCPRequest(request *protocol.RequestHeader, writer io.Writer) (buf.Writer, error) {
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user := request.User
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account := user.Account.(*MemoryAccount)
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var iv []byte
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if account.Cipher.IVSize() > 0 {
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iv = make([]byte, account.Cipher.IVSize())
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common.Must2(rand.Read(iv))
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if err := buf.WriteAllBytes(writer, iv, nil); err != nil {
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return nil, newError("failed to write IV")
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}
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}
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w, err := account.Cipher.NewEncryptionWriter(account.Key, iv, writer)
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if err != nil {
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return nil, newError("failed to create encoding stream").Base(err).AtError()
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}
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header := buf.New()
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if err := addrParser.WriteAddressPort(header, request.Address, request.Port); err != nil {
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return nil, newError("failed to write address").Base(err)
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}
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if err := w.WriteMultiBuffer(buf.MultiBuffer{header}); err != nil {
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return nil, newError("failed to write header").Base(err)
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}
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return w, nil
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}
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func ReadTCPResponse(user *protocol.MemoryUser, reader io.Reader) (buf.Reader, error) {
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account := user.Account.(*MemoryAccount)
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var iv []byte
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if account.Cipher.IVSize() > 0 {
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iv = make([]byte, account.Cipher.IVSize())
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if _, err := io.ReadFull(reader, iv); err != nil {
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return nil, newError("failed to read IV").Base(err)
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}
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}
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return account.Cipher.NewDecryptionReader(account.Key, iv, reader)
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}
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func WriteTCPResponse(request *protocol.RequestHeader, writer io.Writer) (buf.Writer, error) {
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user := request.User
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account := user.Account.(*MemoryAccount)
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var iv []byte
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if account.Cipher.IVSize() > 0 {
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iv = make([]byte, account.Cipher.IVSize())
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common.Must2(rand.Read(iv))
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if err := buf.WriteAllBytes(writer, iv, nil); err != nil {
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return nil, newError("failed to write IV.").Base(err)
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}
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}
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return account.Cipher.NewEncryptionWriter(account.Key, iv, writer)
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}
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func EncodeUDPPacket(request *protocol.RequestHeader, payload []byte) (*buf.Buffer, error) {
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user := request.User
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account := user.Account.(*MemoryAccount)
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buffer := buf.New()
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ivLen := account.Cipher.IVSize()
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if ivLen > 0 {
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common.Must2(buffer.ReadFullFrom(rand.Reader, ivLen))
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}
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if err := addrParser.WriteAddressPort(buffer, request.Address, request.Port); err != nil {
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return nil, newError("failed to write address").Base(err)
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}
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buffer.Write(payload)
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if err := account.Cipher.EncodePacket(account.Key, buffer); err != nil {
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return nil, newError("failed to encrypt UDP payload").Base(err)
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}
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return buffer, nil
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}
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func DecodeUDPPacket(validator *Validator, payload *buf.Buffer) (*protocol.RequestHeader, *buf.Buffer, error) {
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bs := payload.Bytes()
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if len(bs) <= 32 {
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return nil, nil, newError("len(bs) <= 32")
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}
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var user *protocol.MemoryUser
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var err error
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count := validator.Count()
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if count == 0 {
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return nil, nil, newError("invalid user")
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} else if count > 1 {
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var d []byte
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user, _, d, _, err = validator.Get(bs, protocol.RequestCommandUDP)
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if user != nil {
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payload.Clear()
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payload.Write(d)
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} else {
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return nil, nil, newError("failed to decrypt UDP payload").Base(err)
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}
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} else {
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user, _ = validator.GetOnlyUser()
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account := user.Account.(*MemoryAccount)
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var iv []byte
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if !account.Cipher.IsAEAD() && account.Cipher.IVSize() > 0 {
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// Keep track of IV as it gets removed from payload in DecodePacket.
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iv = make([]byte, account.Cipher.IVSize())
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copy(iv, payload.BytesTo(account.Cipher.IVSize()))
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}
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if err = account.Cipher.DecodePacket(account.Key, payload); err != nil {
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return nil, nil, newError("failed to decrypt UDP payload").Base(err)
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}
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}
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request := &protocol.RequestHeader{
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Version: Version,
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User: user,
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Command: protocol.RequestCommandUDP,
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}
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payload.SetByte(0, payload.Byte(0)&0x0F)
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addr, port, err := addrParser.ReadAddressPort(nil, payload)
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if err != nil {
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return nil, nil, newError("failed to parse address").Base(err)
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}
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request.Address = addr
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request.Port = port
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return request, payload, nil
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}
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type UDPReader struct {
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Reader io.Reader
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User *protocol.MemoryUser
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}
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func (v *UDPReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
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buffer := buf.New()
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_, err := buffer.ReadFrom(v.Reader)
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if err != nil {
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buffer.Release()
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return nil, err
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}
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validator := new(Validator)
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validator.Add(v.User)
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u, payload, err := DecodeUDPPacket(validator, buffer)
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if err != nil {
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buffer.Release()
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return nil, err
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}
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dest := u.Destination()
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payload.UDP = &dest
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return buf.MultiBuffer{payload}, nil
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}
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type UDPWriter struct {
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Writer io.Writer
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Request *protocol.RequestHeader
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}
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func (w *UDPWriter) WriteMultiBuffer(mb buf.MultiBuffer) error {
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for {
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mb2, b := buf.SplitFirst(mb)
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mb = mb2
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if b == nil {
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break
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}
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request := w.Request
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if b.UDP != nil {
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request = &protocol.RequestHeader{
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User: w.Request.User,
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Address: b.UDP.Address,
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Port: b.UDP.Port,
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}
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}
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packet, err := EncodeUDPPacket(request, b.Bytes())
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b.Release()
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if err != nil {
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buf.ReleaseMulti(mb)
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return err
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}
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_, err = w.Writer.Write(packet.Bytes())
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packet.Release()
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if err != nil {
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buf.ReleaseMulti(mb)
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return err
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}
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}
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return nil
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}
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